Data Integrity Rules in DBMS

We generally heard a lot about data integrity, primary key, foreign key, etc keywords whenever we are working on Database side or working in software domain no matter as DB developer or any language-specific developer but at last, Database is the core part for all applications.

However, behind every digital application, Data is the only thing which is the core part and to keep it at a place, Database is required. Data is increasing with an exponential rate. As per a recent study, there are 2.5 quintillion bytes of data created each day. So now you can guess the importance of keep data and making sure that it's safe.

Moreover, this article would illustrate some rules/terms regarding database integrity. Kindly have a look at below points and let me know if you have any questions or concerns:

1. Business rules: obtained from users when gathering requirements and are used to determine the cardinality
2. Cardinality: expresses the minimum and maximum number of entity occurrences associated with one occurrence of a related entity
3. Connectivity: the relationship between two tables, e.g., one to one or one to many
4. Constraints: the rules that force DBMSs to check that data satisfies the semantics
5. Entity integrity: requires that every table have a primary key; neither the primary key nor any part of it, can contain null values
6. Identifying relationship: where the primary key contains the foreign key; indicated in an ERD by a solid line
7. Integrity constraints: logical statements that state what data values are or are not allowed and which format is suitable for an attribute
8. Mandatory relationship: one entity occurrence requires a corresponding entity occurrence.
9. Non-identifying relationship: does not contain the foreign key in the primary key; indicated in an ERD by a dotted line
10. Optional relationship: the FK can be null or the parent table does not need to have a corresponding child table occurrence
11. Orphan record: a record whose foreign key value is not found in the corresponding entity – the entity where the primary key is located
12. Referential integrity: requires that a foreign key must have a matching primary key or it must be null
13. Relational database management system (RDBMS): a popular database system based on the relational model introduced by E. F. Codd of IBM’s San Jose Research Laboratory
14. Relationship type: the type of relationship between two tables in an ERD (either identifying or non-identifying); this relationship is indicated by a line drawn between the two tables.